[PATCH 5/5] HPET interaction with in-kernel PIT

Beth Kon
2009-06-11T14:41:51Z

arch/x86/include/asm/kvm.h | 1 +
arch/x86/kvm/i8254.c | 24 +++++++++++++++++++-----
arch/x86/kvm/i8254.h | 3 ++-
arch/x86/kvm/x86.c | 5 ++++-
4 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/kvm.h b/arch/x86/include/asm/kvm.h
index 708b9c3..3c44923 100644
--- a/arch/x86/include/asm/kvm.h
+++ b/arch/x86/include/asm/kvm.h
@@ -235,6 +235,7 @@ struct kvm_guest_debug_arch {

struct kvm_pit_state {
struct kvm_pit_channel_state channels[3];
+ u8 hpet_legacy_mode;
};

struct kvm_reinject_control {
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 331705f..bb8382b 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -340,10 +340,20 @@ static void pit_load_count(struct kvm *kvm, int channel, u32 val)
}
}

-void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val)
+void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start)
{
+ u8 saved_mode;
mutex_lock(&kvm->arch.vpit->pit_state.lock);
- pit_load_count(kvm, channel, val);
+ if (hpet_legacy_start) {
+ /* save existing mode for later reenablement */
+ saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
+ kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
+ pit_load_count(kvm, channel, val);
+ kvm->arch.vpit->pit_state.channels[0].mode = saved_mode;
+ } else {
+ if (!(channel == 0 && kvm->arch.vpit->pit_state.hpet_legacy_mode))
+ pit_load_count(kvm, channel, val);
+ }
mutex_unlock(&kvm->arch.vpit->pit_state.lock);
}

@@ -411,17 +421,20 @@ static void pit_ioport_write(struct kvm_io_device *this,
switch (s->write_state) {
default:
case RW_STATE_LSB:
- pit_load_count(kvm, addr, val);
+ if (!(addr == 0 && pit_state->hpet_legacy_mode))
+ pit_load_count(kvm, addr, val);
break;
case RW_STATE_MSB:
- pit_load_count(kvm, addr, val << 8);
+ if (!(addr == 0 && pit_state->hpet_legacy_mode))
+ pit_load_count(kvm, addr, val << 8);
break;
case RW_STATE_WORD0:
s->write_latch = val;
s->write_state = RW_STATE_WORD1;
break;
case RW_STATE_WORD1:
- pit_load_count(kvm, addr, s->write_latch | (val << 8));
+ if (!(addr == 0 && pit_state->hpet_legacy_mode))
+ pit_load_count(kvm, addr, s->write_latch | (val << 8));
s->write_state = RW_STATE_WORD0;
break;
}
@@ -548,6 +561,7 @@ void kvm_pit_reset(struct kvm_pit *pit)
struct kvm_kpit_channel_state *c;

mutex_lock(&pit->pit_state.lock);
+ pit->pit_state.hpet_legacy_mode = 0;
for (i = 0; i < 3; i++) {
c = &pit->pit_state.channels[i];
c->mode = 0xff;
diff --git a/arch/x86/kvm/i8254.h b/arch/x86/kvm/i8254.h
index b267018..b5967ca 100644
--- a/arch/x86/kvm/i8254.h
+++ b/arch/x86/kvm/i8254.h
@@ -21,6 +21,7 @@ struct kvm_kpit_channel_state {

struct kvm_kpit_state {
struct kvm_kpit_channel_state channels[3];
+ u8 hpet_legacy_mode;
struct kvm_timer pit_timer;
bool is_periodic;
u32 speaker_data_on;
@@ -49,7 +50,7 @@ struct kvm_pit {
#define KVM_PIT_CHANNEL_MASK 0x3

void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu);
-void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val);
+void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start);
struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags);
void kvm_free_pit(struct kvm *kvm);
void kvm_pit_reset(struct kvm_pit *pit);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 1b91ea7..3c70545 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1948,9 +1948,12 @@ static int kvm_vm_ioctl_get_pit(struct kvm *kvm, struct kvm_pit_state *ps)
static int kvm_vm_ioctl_set_pit(struct kvm *kvm, struct kvm_pit_state *ps)
{
int r = 0;
+ int hpet_legacy_start = 0;

+ if (ps->hpet_legacy_mode && !kvm->arch.vpit->pit_state.hpet_legacy_mode)
+ hpet_legacy_start = 1;
memcpy(&kvm->arch.vpit->pit_state, ps, sizeof(struct kvm_pit_state));
- kvm_pit_load_count(kvm, 0, ps->channels[0].count);
+ kvm_pit_load_count(kvm, 0, ps->channels[0].count, hpet_legacy_start);
return r;
}